You are clearly too young to remember the rage people had back then.
WinXP was "Busy" compared to Win98. Those who wanted busier, more colorful schemes could always install a color pack or customize their windows as appropriately.
WinXP released with basically one colorpack, and removed the option of going back to the older "classier" gray look from Win98 / Win95.
The Win8.x metro colors look like chosen by a color blind person. Or to celebrate the 30th anniversary of Windows 1.0 by a retro color theme.